If you ever have problems activating Microsoft Office 2013 you might need to change the licence key, but this cannot be done through the front end.
Instead, there is a command you can run at the command line to change the key:
cscript "C:\Program Files (x86)\Microsoft Office\Office15\OSPP.VBS" /inpkey:officekey
Replace the highlighted section above to the new key you want to put in place; once done you can then log into Office and activate the software online.
